Gas fuel mixing device



June 29, 1937. F. G. WELKE GAS FUEL MIXING DEVICE Filed May 2l, 1935 2Sheets-Sheet l m Il V..

June 29, 1937. F. G. WELKE 2,085,243

GAS FUEL MIXING DEVICE Filed May 21, 1955 2 `Sheets-Sl'xeei 2carburetor.

Patented June 29, 1937 vPATENT OFFICE GAs FUEL MIXING DEVICE FerdinandlG. Welke, San Francisco, Calif., as-

signor to Shell Development Company, San Francisco, Calif., acorporation of Delaware Application May 21, 1935, Serial No. 22,539

v 1 Claim.

the intake manifold of an internal combustion motor.

It has for some time been the practice in certain localities to operateinternal combustion motors on gaseous fuel for example propane, butane,methane and various other gaseous hydrocarbon mixtures such as coal gas,oil gas etc.

Underconditions of fairly constant speed and loadV as for example whereinternal combustion motors are used for pumping or the generation ofelectricity the operation on gaseous fuel has been quite satisfactory.However where motorized units such as automobiles, buses andtrucks havebeen operated on such gaseous fuels considerable trouble has beenexperienced due to the inability to obtain the desired power andacceleration under all driving conditions.

Such deficiencies in power and acceleration at certain load and speedconditions of the motor are commonly7 known as flat spots.

It is an object of this invention to devise an apparatus which willeliminate flat spots in the operation of a I notor on gaseous fuel.Another object of Ythis invention is to devise a gas mixing device whichwill deliver the correct proportion of air and 'gas to the motor overthe entire operation range. A further object of this invention is toprovide a gas fuel mixing device which may be readily fitted to thecarburetor air intake of an internal combustion motor fitted with a.gasoline The further objects of this invention will be apparent tothoseskilled in the art from the following 'detailed description of aspecific embodiment of my invention throughout which reference is madeto the accompanying drawings of which,

Fig. Iis 4an end elevation of the gas mixing device' partly in section.

Fig. II is a vertical section along Aline 2-2 of Fig. I.

Fig. III is a plan view of ilapper valve.

Fig. IV is a side elevation of the iiapper valve.

Fig. V is an elevation showing the device in position and connected foroperation.

buretor of an internal combustion motor. The plate (2) is provided withan air inlet port (5) and a gas inlet port (6) arranged with theircenters on a common vertical line. The air inlet port is provided on itsexterior side with a concentrically mounted collar (1) which togetherwith the port (5) forms the air inlet. The gas inlet port (6) isprovided on its exterior side with an adjusting flange (8). The ange (8)is attached to the plate by means of machine screws passing throughopenings in the flange. One of said openings is slot shaped so that theflange '(8) may be moved laterally on the plate (2). Screwthreaded intoa central opening in the flange (8) is a gas nozzle (9). The distance towhich the gas nozzle is screwed into the flange is adjusted bymeans ofan adjusting collar (I) and locking nut (I I) the latter beingscrew-threaded onto the nozzle (9). Covering the air and gas ports (5)and (6) is a flapper or plate valve (I2) hinged to the interior wall ofthe body above the gas port (E) by means of a hinge pin (I3). Theflapper valve, the details of which can be seen in more detail byreferring to Figures III and IV, is of such size that it covers the gasport (6) and air port when the valve is in vertical position as shown inFig. II. A spring (I4) is coiled around the hinge pin (I3) and attachedat one end to the middle of the plate on its inward side by a machinescrew and nut (I5). In assembled position as shown in Fig. II the otherend of the spring (I4) contacts the opposite interior wall `of the body(I). The flapper (I2) is perforated in its upper midsection at (I6) asshown in Fig. III at a. point above air port (5) and below gas port (6)and for a reason which will hereinafter appear.

A second spring (Il) having its mid point attached to the middle of thefiapper (I2) by the means shown at (I5) is so arranged that its freeends (Il) press against the plate (2) when the dapper valve is closed,tending to force the flapper away from its closed position. The secondspring (Il) is not as strong as the spring (I4) consequently the valvenormally rests in closed position.

The object and function of this second spring will be explained laterherein. The slanting face (I8) of the body (I) has a port (I9) so thatthe interior of the device can be placed in communication with theoutside air. This port I 9) is normally kept closed by means of anoutwardly opening valve (2U) held in closed position by a leaf spring(ZI), one end of said spring being attached to the center of the valve(2D) and the other end being attached to the body, as will be Seen inFigure II. As shown in Figure V the de- I vice above described isattached at its lower end (3) to the carburetor air intake (4) of aninternal combustion motor (33) by a suitable connecting means (36). Thegas nozzle is connected by suitable flexible hose (22) to the outletside of a gas regulator (23) so adjusted that gas will pass to thedevice upon the creation of a vacuum in the hose (22). The gas regulatoris of conventional type and is shown in section in Fig. VI. Referring tothis figure, the gas inlet piece (24) vis connected to a source of gasunder pressure and is closed at its termination point within theregulator body by a valve (25). The valve (25) is connected to one endof an arm v(26) pivoted to the body at point (21). The other end of thearm is connected to the middle of a diaphragm (28) closing the interiorof the regulator from the outside air. An adjustable spring (29) pushesagainst the arm (26) at the point where it is connected to the diaphragm(28) gas leaves theregulator by outlet pipe (30). The operation is asfollows: Upon the lowering of the pressure in the outlet pipe (30) thediaphragm (28) movesupwards, and through the arm l(26) causes the valve(25) to open allowing gas to enter the regulator. Upon the pressure inthe regulator being raised, the diaphragm moves downward and shuts offthe incoming gas supply. The regulator works automatically to maintain afairly constant subatmospheric pressure in the hose (22)vnotwithstanding the varying amounts of gas flowing through. The amountof vacuum required to cause the ow of gas can be regulated.

I have found in practice that if the regulator is set to allow gas to owthrough the hose (22) with a subatmospheric pressure of twov inches ofwater below atmospheric, satisfactory operation is obtained. lit shouldhowever, be borne in mind that the setting of the/ regulator for thebest Iperformance will depend upon many factors among which may bementioned the distance between the regulator and gas mixer, the tensionof spring (I4) the type of manifolding on the motor etc., so that theadjustment of the regulator is preferably made for each individualinstallation by the engineer installing the same.r When 4using thegas-air mixture the gasoline supply to the carburetor is shut off. Thecross sectional areas ofthe gas nozzle (9) and the air port (5) as vwellas the distances of the gas nozzle and the air port from the hinge pinare so proportioned that the correct gas-air mixture is supplied to themotor. 'Forexampla when using propane with my device fitted to the airintake of a down draft carburetor of a particular motor I have foundthat with a diameter'of the gas nozzle of .3116", diameter of air port1.5", distance of center of gas nozzle from the'hinge pin .5", distanceof center of air port to hinge pin, 2.75", a correct fuel-air ratiov wasmaintained. The gas nozzle (9) can by means of the flange (8) be movedslightly towards or away from the hinge pin (I3) by loosening thermachine screw passing through the slotted opening in the flange (8). Bythis means the ratio of gas to air may be adjusted. By moving the gasnozzle laterally towards.` the hinge pin (I3) the proportion of gas inthe mixi ture is reduced, by moving the nozzle laterally away from thehinge pin (I3) the proportion of gas in the mixture is increased. Theproportion of gas to air in the -idling mixture is adjusted by screwingthe gas nozzle either inward towards the iiapper or outward away fromthe apper byk means of adjusting collar (I0) The operation of the deviceis as follows: Upon the opening of the .throttle valve (3|) of thecarburetor (35) and the turning over of the motor (33) by means of theelectric starter or otherwise, a partial vacuum is produced in theinterior ofthe device suflicient tocause the flapper (I2) to raise fromcontact with the plate (2) so that air from the atmosphere and gas fromthe pressure side of the gas regulator are drawn into the motor as witha gasoline-air mixture.

Once the motor has started it will continue vto run on the gas-airmixture, the amount of I do not intend to limit myself to this theory.

In practice I have `found that the spring (I1) is effective inpreventing vibration or fluttering of the flapper valve when otherattempts to prevent this were unsuccessful.

The provision ofthe opening (I6) in the flapper valve (I2) between thetwo ports (5) and (6) is for the purpose of permitting a'more ready.entry of gas from port (6) into the body of the device and to helpmaintain the correct gas-air ratio. The provision of the relief valve(20) is to provide a relief for the gases in the event of backfire ofthe motor for it will beapparent from the drawing that thegases would beunable to leave by way of the air inlet as i's possible with the usualgasoline carburetor. 'I'he particular device shown is designed forattachment to the air intake of an existing gasoline carburetor so thatby turning off the gasoline feed and turningon the gas feed, the motormay be run on gas-air mixture or by turning on the gasoline feed andturning oif the gas feed the motor may be operatedon gasoline-airmixture. In installations where it is only desired to run on a gas-airmixture the device of my invention can be provided with a throttle valve(32) in its outlet toward the motor as shown in dotted lines in Fig. II.The unit in this case is attached directly to the induction manifold ofthe motor (33) without the intermediary of acarburetor.

I claimas my invention? In a gas fuel mixing device for, an internalcombustion motor, the combination of an air inlet port, a gas inletport, a flapper valve covering said ports, a first springY holding saidflapperl valve in contact with said ports, a second spring tending tohold said flapper valve away from said ports whereby periodic vibrationof said flapper valve is prevented.

FERDINAND G. WELKE.

